* Annual estimated passenger usage based on sales of tickets in stated financial year(s) which end or originate at Llangynllo from Office of Rail Regulation statistics. Methodology may vary year on year.
Llangynllo railway station is a countryside stop in Powys about 5 miles west of Knighton, on the line between Llanelli and Craven Arms. The railway station is located at road level beside two houses on a minor rural road off the B4356 road.
All trains serving the station are operated by Arriva Trains Wales. There are four trains a day in each direction from Monday to Saturday, and two services on Sundays. This is a request stop, where passengers have to signal to the driver to board or alight from the train. The highest point on the line (some 980 ft (270 m) above sea level) is a short distance to the north of the station.